1. Field of the Invention
This invention relates to modeling lightweight dough for hand crafting used by a worker, such as children and artist.
2. Description of the Prior Art
Heretofore, dough has been used for hand crafting. Generally, dough is plastic so as to be used for forming, can be deformed into a desired shape by hands to form a craft, dried naturally to harden it, and the shape of the craft can be maintained for a long time. Inorganic heavyweight clay has been used previously as the main component of the dough; however, currently lightweight dough has been used widely instead of heavyweight clay because of easy modeling and easy carrying. Lightweight dough that contains, for example, lightweight hollow microspheres as the major component in volume, and binder, fiber powder, and water as the minor component in volume has been known.
An example of lightweight dough containing hollow microspheres, polyvinyl alcohol, polyvinyl alcohol gelling agent, and water has been proposed in U.S. Pat. No. 5,506,280 to realize the lightweight dough.
However, the above-mentioned lightweight dough is not sufficient in formability or workability. In detail, it is necessary for the dough to be rendered non-sticky to hand, easily deformable, stably ductile for forming to a fine shape, smooth on the surface of the stretched shape, and long shape preservation of the modeled product. However, the conventional lightweight dough does not sufficiently satisfy the above-mentioned requirements. In detail, the conventional lightweight dough is still sticky to hand, hard to deform easily, too elastic to stretch dough to obtain a desired shape even though it is deformed, not sufficiently smooth on the stretched surface, or insufficient in shape preservation after modeling. Furthermore, a modeled product made of the conventional dough becomes brittle after modeling and drying, and is poor in deformation resistance, that causes the breaking of the model product when the external force is exerted. The conventional dough is disadvantageous as described hereinabove, the craft modeled by use of the conventional dough cannot be maintained stably, and the long time preservation is difficult due to weakness to the external force.
It is an object of the present invention to provide modeling dough that is lightweight so that children can lift and carry it easily for modeling and can carry the modeled craft easily.
It is another object of the present invention to provide modeling dough that gives comfortable hand feeling to a worker during modeling, is suitably ductile so that it is easily deformable to a desired shape by use of a force of the hand during modeling, is smooth on the deformed surface, and is suitably hard so that the modeled shape is maintained and excellent in shape preservation.
It is still another object of the present invention to provide modeling dough that is not sticky to the hand of a worker during modeling, excellent in releasability, stain-resistant on hand and clothes of a worker, and enables comfortable modeling work.
It is a further object of the present invention to provide modeling dough that forms a modeled product obtained by modeling and drying of the dough of the present invention excellent in resistance to bending deformation and a model product excellent in long preservation.
The present invention provides a modeling dough comprising synthetic resin hollow microspheres having a particle diameter of 20 to 120 xcexcm, polyvinyl alcohol, vinyl acetate resin, and water, and a modeling dough comprising synthetic resin hollow microspheres having a particle diameter of 20 to 120 xcexcm, polyvinyl alcohol, vinyl acetate resin, polyethylene oxide, and water.
The synthetic resin hollow microspheres used in the present invention are hollow microspheres formed by heating synthetic resin heat-expandable minute spheres containing low-boiling point hydrocarbon or the like. The synthetic resin used is desirable various copolymers selected from vinylidene chloride, acrylonitrile, and acrylic ester, but not limited to these copolymers. The particle diameter of the synthetic resin hollow microsphere is desirably 20 to 150 xcexcm. The specific gravity of the synthetic resin hollow microsphere is desirably about 0.01 to 0.04. Usually, aqueous dispersion of the synthetic resin hollow microspheres that contain some water (containing 70 to 90% by weight of water) is commercially available, and such synthetic resin hollow microspheres may be used.
The content of synthetic resin hollow microspheres is preferably 5 to 15% by weight (based on dry weight) to the total weight of the dough. If the content is less than 5% by weight (other components are contained much), then the dough is likely sticky and not sufficient in formability, and likely not sufficient in lightweight property of the dough; on the other hand, if the content is more than 15% by weight, then the modeled product is apt to be weak to the external force.
Because the synthetic resin hollow microspheres used in the present invention are lightweight, the volume in the dough of the present invention are very large, and the synthetic resin hollow microspheres occupy the majority of the dough volume. Furthermore, because the hollow microsphere is spherical, there are spaces among hollow microspheres, spaces accommodate water and other ingredients that form soft mixture so as to be movable during modeling and so as to make modeling or manuplating easy. Because only water the majority of which is in the space among hollow microspheres is evaporated during drying, the volume scarcely changes with concomitant change from wet state to dry state, and the modeled product is excellent in shape preservation.
Polyvinyl alcohol used in the present invention is partially hydrolized polyvinyl acetate, and the degree of hydrolysis is desirably 80 to 95 mol %, and more desirably 85 to 90 mol %. Polyvinyl alcohol in the form of powder or aqueous solution is used herein, and powder is usually used. Fine powder is desirably used so that powder does not coagulate each other when the powder is mixed with water.
Modified polyvinyl alcohol having a high viscosity of 400 to 900 mpa.s measured under conditions of 3% aqueous solution at 20xc2x0 C. is used desirably as the polyvinyl alcohol used in the present invention.
Polyvinyl alcohol functions to bind hollow microspheres maintaining plasticity during modeling and to maintain the shape of the modeled product after modeling and drying.
The content of polyvinyl alcohol is preferably 5 to 10% by weight to the total dough (expressed in dry weight base), and more preferably 5 to 8% by weight. If the content of polyvinyl alcohol is less than 5% by weight, then the plasticity and ductility is likely not sufficient; on the other hand, if the content exceeds 10% by weight, then the dough is too hard, and the workability for modeling and hand feeling property become likely poor.
Examples of vinyl acetate resin used in the present invention include vinyl acetate based resins, such as polyvinyl acetate, modified polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl acetate-acrylic acid copolymer, vinyl acetate-acrylic ester copolymer, vinyl acetate-methacrylic acid copolymer, vinyl acetate-methacrylic ester copolymer, and vinyl acetate-acryl amide copolymer. Vinyl acetate resin is used in the form of powder or emulsion, and usually emulsion is used. An emulsion containing vinyl acetate resin component of 50% or more is desirably used.
Vinyl acetate resin having a viscosity of 1,000 to 150,000 mpa.s measured under conditions of 59% aqueous solution at 30xc2x0 C. is preferable used in the present invention.
Vinyl acetate resin functions to bond hollow microspheres together with polyvinyl alcohol with maintaining plasticity during modeling, and functions to maintain the shapes of the modeled product after modeling and drying.
Vinyl acetate resin emulsion containing plasticizer is desirably used. Dibutyl phthalate or the like is exemplified as the plasticizer. The content of plasticizer is desirably 4 to 10% by weight to the emulsion weight.
The content of vinyl acetate resin is preferably 1.5 to 6% by weight (expressed in dry weight base), and more preferably 2 to 5% by weight.
The mixed use of polyvinyl alcohol and vinyl acetate resin is required to bond hollow microspheres with maintaining good softness during modeling and to maintain the shape of the modeled product after modeling and drying. Dough should be sufficiently plastic when it is wet so as to be modeled by hand of a child, and should be sufficiently ductile so as to be stretched to form thin or fine shape, and furthermore should be suitably hard (shape preservation) so as to maintain the modeled shape. The mixed use of polyvinyl alcohol and vinyl acetate resin satisfies these conditions. Furthermore, dried dough should not be cracked and should not be brittle, and should be resistant to deformation such as bending.
The mixing ratio of polyvinyl alcohol to vinyl acetate resin is desirably 10:7 to 10:3 by weight. If the mixing ratio of vinyl acetate resin exceeds 7, then dough is likely sticky and likely poor in formability, on the other hand if the mixing ratio is smaller than 3, then the breaking resistance to the external force is likely poor after drying.
Polyethylene oxide used in the present invention is a polymer obtained by ring-opening polymerization of ethyleneoxide, and is a water-soluble high polymer having ether groups in the middle part and hydroxyl groups at the ends. Polyethylene oxide having a molecular weight of approximately 300,000 to 1,200,000, more desirably 600,000 to 800,000 is used in the present invention. Such polyethylene oxide exhibits a very high viscosity even though it is a solution of a very low concentration, and the viscosity measured under conditions of 2.0% by weight solution at 25xc2x0 C. is preferably 100 to 2000 mpa.s, more desirably 200 to 700 mpa.s (measured by means of a rotational viscometer). Polyethylene oxide having a melting point of 65 to 67xc2x0 C. is desirable. Such polyethylene oxide is excellent in compatibility with synthetic resin hollow microspheres, polyvinyl alcohol, and vinyl acetate.
Powder or aqueous solution of polyethylene oxide is used, and usually polyethylene oxide powder is used. Polyethylene oxide fine powder is desirably used so as not to coagulate each other when it is mixed with water.
Polyethylene oxide functions to improve the plasticity and ductility of dough when it is modeled, and to improve the stickiness of the dough to thereby reduce sticking to hand, and the forming workability is improved. Surface smoothness of the modeled product are more improved by adding polyethylene oxide.
The content of polyethylene oxide is preferably 0.5 to 1.5% by weight to the total dough (expressed by dry weight base).
Dough of the present invention may be mixed with fiber powder in addition to the above-mentioned substances.
Fiber powder functions to improve the shape preservation after modeling and drying, and to exhibit the shrinkage prevention effect. Pulp powder, polyvinyl alcohol based fiber powder, cotton powder, and crashed sheet pulp are exemplified as the above-mentioned fiber powder. The natural or synthetic fiber powder having a length of 0.05 to 5.5 mm, more desirably 1 to 3 mm is used. The content of the fiber powder is preferably 0.5 to 4% by weight to the total dough weight.
Dispersant may be added to dough of the present invention in addition to the above-mentioned components. Higher alcohol sulfuric ester, polyoxyethylene laurylether sulfate sodium salt, and high polymer polycarboxylic acid are exemplified as the above-mentioned dispersant. Polyoxyethylene laurylether sulfate sodium salt is particularly desirable. The content of dispersant is preferably 2 to 8% by weight (% by weight of 25% aqueous solution) to the total dough weight.
Other than the above-mentioned components, carboxy methyl cellulose, methyl cellulose, hydroxy methyl cellulose, hydroxy ethyl cellulose, natural high polymer guargum, guargum derivatives may be added to the dough of the present invention. These substances function to improve the ductility, surface smoothness, and hand feeling of dough, the content of these substances is preferably 0.5 to 1.5% by weight to the total dough weight.
Humidifier may be added to dough of the present invention in addition to the above-mentioned components. Liquid paraffin, sorbitol, polyethylene glycol, polypropylene glycol or the like are exemplified as the humidifier. The content of humidifier is preferably 0.5 to 1.5% by weight to the total dough weight.
Furthermore, the content of water is preferably 50 to 80% by weight to the total dough weight, and more preferably 60 to 75% by weight.
Because dough of the present invention contains lightweight hollow microspheres as the major component in volume, dough of the present invention is so lightweight, children can lift it easily during modeling and carry it easily, and the modeled product can be carried easily.
Dough of the present invention contains hollow microspheres as the major component in volume that is fine and is soft, hand feeling of the dough is comfortable for a worker, dough is suitably soft for deforming it easily to form a desired shape by force of hand during modeling, dough is suitably hard for maintaining the modeled shape during modeling and excellent in shape preservation, and thus the dough is excellent in formability.
Furthermore, dough of the present invention will not stick to the hand of a worker during modeling, and will not stain the hand and clothes of a worker because of the good releasability, the comfortable modeling work is realized.
Dough of the present invention provides a modeled product obtained by modeling and drying that is resistant to bending deformation, and thus it is suitable for long time preservation.